Apparatus for feeding gas into molten metal baths



May 9, 1950 E. A. JOHNSON, JR 2,506,598

APPARATUS FOR FEEDING GAs INT0 MoLTEN METAL BATHs Filed Jan. 22, 1948'IN VEN TOR.

AGEN T Patented May 9, 1950 APPARATUS FOR FEEDING GAS INTO MOLTEN METALBATHS Evan A. Johnson, Jr., New York, N. Y., assignor to HydrocarbonResearch, Inc., New York, N. Y., a corporation of New JerseyApplicationianuary zz, 194s, serial No. 3,668

5 Claims. l

This invention relates to apparatus for introducing a gas, such asoxygen or oxygen-enriched air, into a bath of molten metal.

The introduction of oxygen or oxygen-enriched air into a bath of moltenmetal, for example, molten iron in an open hearth furnace to acceleratethe rate of reduction of the carbon content of the molten iron, hasreceived and is receiving considerable attention by research personnel.In order to obtain satisfactory results it has been found necessary tointroduce the oxygen beneath the surface of the bath of molten ironWhere it will come into intimate contact with the carbon and effect itsremoval. Obviously the introduction of oxygen through a steel or ironpipe having its exit end disposed beneath the surface of the molten ironresults in melting and/or oxidation of the pipe at a rate requiringrapid replacement of the pipe. In fact it has been suggested to use along steel pipe or so-called lance, say about 20 feet long or longer,mounted on a carriage with one end immersed in the molten metal, thepipe being moved into the molten metal to replace the end portion as thelatter is consumed while feeding oxygen through this pipe into themolten bath. Such equipment has many disadvantages, among which may bementioned (1) it involves the use of a cumbersome carriage for the longlengths of pipe, which carriage and'lengths of pipe occupy the spacenear the open hearth furnace and therefore obstruct and otherwiseinterfere with the movement of the operators and furnace charging carsin the vicinity of the furnace, (2) it entails frequent interruption ofthe feed of the oxygen into the molten bath necessitated by theplacement of new lengths of pipe on to the carriage and the connectionof such pipe with the source of oxygen, (3) it involves arduous andtime-consuming labor for servicing and operating the carriage whicheffects feeding of the length of pipe into the molten metal bath, (4) itnecessitates stock piling long lengths of pipe in the vicinity of themolten metal bath, and

(5) only about 50% of the length of each lance is consumed before thelance is too short and must be discarded.

It is an object of this invention to provide apparatus for introducing agas such, for example, as oxygen or oxygen-enriched air below thesurface of a bath of molten metal, e. g., a bath of molten iron in anopen hearth furnace, which apparatus is compact, requires little spacein the vicinity of the bath, is simple to construct, is eilicient inoperation and requires little attention by the operator.

Other objects and advantages of this invention will be apparent from thefollowing detailed description thereof. Y

In accordance with this invention a reel having any desired length ofmetal pipe Wound thereon is disposed near the bath of molten metal. Oneend of the wound pipe is continuously or intermittently unwound from thereel by a feeding device which desirably straightens the pipe and causesthe leading end to project into the bath of molten metal beneath thesurface thereof. Gas is supplied to the other end of the pipe passingthrough the convolutions on the reel and flowing through the leading endof the pipe entering the bath beneath the surface thereof. The pipe isunwound at a rate corresponding to the rate at which the end of the pipeimmersed in the bath of molten metal is consumed; for example, the pipemay be unwound at a rate of about 0.1 to 10 linear feet per minute.

The reel provides in compact form unusually long lengths of pipe, enoughto permit introduction of the gas beneath the surface of the moltenmetal for several hours without interrupting the supply of gas.Furthermore, the reel and the feeding mechanism associated therewithoccupy relatively little space in the vicinity of the bath and may be sodisposed that they do not interfere with the movement of the operators.feeding mechanism associated with the reel automatically feeds straightlengths of pipe at the desired rate and effects straightening of thepipe as fed requiring practically no attention on the part of theoperator except when the pipe on the reel has been consumed. The reel,if desired, may be so designed as to carry a length of pipe sumcient tolast throughout the decarburization period, thus necessitating noreplacement of the reel during the decarburization period, a fresh lreel preferably being installed at the commencement of a new heat.

In the preferred embodiment illustrated on the drawing the invention isshown incorporated in an oxygen feeding device for an open hearth furfnace and the description which follows will be confined to the presentillustrated embodiment of the invention. It will be understood, however,that the novel features and improvements are susceptible to otherapplications such, for example, as feeding devices for feeding othergases than oxygen into baths of molten metal, including molten iron andother molten metals in electric, open hearth and other furnaces. Hence,the scope of this invention is not confined to the embodiment hereindescribed.

Thel

3 In the accompanying drawing forming a part of this specification andshowing for purposes of exemplication a preferred form of this inventionwithout limiting the claimed 'invention to such illustrative instance. l

Figure 1 is a fragmentary vertical section through an open hearthfurnace showing schematically in side elevation an oxygen feeding delvice associated therewith;

Figure 2 is an enlarged plan view of the ongen feeding device of Figure1;

Figure 3 is a side elevation corresponding to the view of the oxygenfeeding device show n in Figure 2.

Figure 4 is a vertical section taken in a plane v passing through line4-4 of Figure 3.

Pipe I1 is wound on reel I8, desirably consisting of a pair of circularside plates I9 and 20 having openings 2| therein to reduce the weight ofthese plates. Each of the side plates is formed integral with orfastened to a hub 22 keyed to a hollow shaft 23. A cylindrical shell orpipereceiving member 24 is disposed, as shown in Figures 3 and 4, belowthe edges of the plates I9 and to provide a cylindrical trough 25 forre` ception of convolutions of the pipe I1. Plates I9 and 20 and member24 may be cast in one piece or may be formed by welding the side platesto the pipe-receiving member 24. Trough 25 is made of suilicient depthto receive several convolutions of the pipe such as to provide a totallength of pipe which will permit continuous introduction of oxygen intothe open hearth furnace over a period of several hours, desirablythroughout the entire melt.

A connecting pipe 26 has one end threaded into a threaded opening inshaft 23, extends therefrom and is provided with a coupling 21 at theother end. Coupling 21 joins end 28 of pipe I1 extending through opening29 in pipe-receive ing member .24 to the connecting pipe 26. Whenwinding pipe I1 on reel I8, end 28 is passed through opening 29, iscoupled by coupling 21 forming a gas tight joint with connecting pipe 26and then pipe I1 is wound on the reel I8 form ing the convolutions 30. Acontinuous uninter-` rupted passage is thus provided through hollowshaft 23, connecting pipe 26 and the interior of pipe I1 to the exit endI6 of this pipe.

The reel I8, it will be noted, consists of side plates I9 and 2U,pipe-receiving member 24, the convolutions of pipe thereon having end 2Sof the pipe fastened through coupling 21 to pipe connection 26 and thehollow shaft 23 -with the interior of which pipe 26 communicates. Thisreel is removably mounted for rotation in a pair of bearing supports 3|and 32, desirably in the form` of plates resting ona suitable standard33 disposed near the open hearth furnace III. Supports 3| and 32 may bebolted or otherwise secured to standard 33. A bearing 34 is disposed inthe upper corner 35 of each of the bearing supports 3| and 32. Corner35, it will be noted, is the corner remote from the open hearth furnaceso that the reel can readily be removed from and replaced in itsbearings 34. Desirably these bearings are of substantially U-shapepermitting the ready insertion therein and removal therefrom of thehollow shaft 23 of the reel I8. Each of the bearing supports 3| and 32is provided remove the reel I8 itis only necessary to removev bolts 39and swing the latch members about their pivot 31.

Each of the bearing supports 3| and 32 is provided with a bearing arm 40in which is rotatably mounted an idler roll 4I desirably having aconcave surface as shown in Figure 2. Disposed adjacent to bearing arm4|) and extending from each of the plates 3| and 32 is a bearing supporting member 42 in which is slidably positioned a bearing mounting 43 fora second idler roll 44. Desirably roll 44 is of the same size and shapeas idler roll 4I but is positioned above idler roll 4| so that as thepipe I1 is caused to move between these two idler rolls, idler roll 4 Iengages the under side of the pipe and idler roll 44 the top of thepipe. A threaded bolt 45 engages the bearing support 43 for the idlerroll 44 and is employed to adjust the position of idler roll 44 withrespect to xed roll 4| to exert the desired pressure on the pipe toeffect straightening thereof as it is fed through the idler rolls 4I and44 by the feeding mechanism hereinafter described. The idler rolls 4Iand 44 thus function to straighten the pipe I1 as it is unwound fromreel I8 so that the freev end of the unwound pipe is substantially freeof kinks and extends in a substantially l straight line direction.

A pair of feed rolls 46 and 41, desirably of concave shape and serratedsurface, are rotatably mounted in the bearing plates 3| and 32` next toidler roll 44. Keyed to the shafts of these feed rolls are a pair ofmeshing gears 48 and 49. The shaft having gear 49 keyed thereto has alsokeyed thereto a drive gear 58 driven by a worm 5| on the armature shaftof a variable speed motor 52. Motor 52 is carried by a bracket 53 boltedor otherwise secured to bearing support 32. Motor 52, when energized,drives the feed rolls 46 and 41 at a selected rate of speed to feed pipeI1 to maintain the free end I6 thereof continually immersed in the bodyof molten iron I2. The linear rate of movement may vary from about 0.1to l0 feet per minute, the exact rate depending upon continuous orintermittent feeding, the temperatureof the moltenmetal, the-type ofpipe used, etc., and in all cases being so chosen that the free end I6of the pipe is maintained beneath the surface of the molten bath.

.An oxygen supply pipe 54 is disposed contiguous to bearing pate 32 andis provided with a rotatable coupling 55 arranged to |be threadily orotherwise connected with end 56 of hollow shaft 23. 'I'he other end ofthis hollow shaft is provided'with a suitable plug 51.

In operation, a reel of steel pipe having end 28 connected through pipe26 with hollow'shaft 23 is rotatably mounted in bearings 34, the latches36 bolted in place and oxygen supply line 54 connected with end 56 ofhollow shaft 23. End I6 of pipe I1 is then threaded through thestraightening rolls 4I `and 44 into the bite between the feed rolls 46and 41. Oxygen is then turned on and variable speed motor 52 energizedto drive the feed rolls 48 and 41. The action of the feed rolls unwindsthe pipe from reel I8 rotating in u bearings 34, pulls the unwound pipethrough straightening idler rolls 4I and 44 and projects the extendingend IB through opening I5 into the bath of molten iron beneath thesurface thereof. Since the reaction takes place at the exit end of thepipe where the exiting oxygen reacts with the contents of the moltenmetal bath, which reaction is exothermic, the highest temperature is inthe locality'of the exit end. This end therefore melts first and byfeeding the pipe at a controlled predetermined rate the end which meltsis replaced so that the introduction of oxygen into the molten bath maybe continued without interruption.

The melting steel pipe obviously does not impair the composition of themolten iron bath. When melting metals other than iron in which iron isan objectionable impurity, a pipe should be chosen of a metal which whenmelted does not result in the incorporation of objectionable impuritiesin the melt.

When the pipe has been unwound from the reel to the point where onlyabout a single turn of pipe remains on the reel, motor 52 isdeenergized, the feed of oxygen is stopped, coupling 21 is disconnected,motor 52 is again energized until the end of the pipe previouslyconnected to coupling 21 has .passed through feed rolls ,45 and 41, andthe terminal piece of pipe thus released from the feeding device of thisinvention is permitted to drop into the furnace or, if preferred, iswithdrawn from the furnace and discarded. Coupling 55 is thendisconnected, bolts 39 removed, latch members 36 swung open, reel I8removed from its bearings 34 and replaced by a new reel. Alternatively,when the end of the pipe previously connected to coupling 21 has almostreached idler roll 4I, motor 52 is stopped, reel I8 is removed from itsbearings 34, a new reel put in place and the leading end of the pipethereon brought into contact with the terminal end of the pipe stillheld between the feed rolls 46 and 41. The two contacting pipe ends arewelded together and thereafter Vthe feeding of pipe into the furnace maybe resumed. After the pipe ends have been joined the flow of gas throughlthe pipe and into the molten bath may again be initiated.

It is to be understood that Figure 1 is not a scaled drawing butrepresents schematically one illustrative arrangement of the feedingdevice of this invention and a furnace holding a molten metal bath. Thefeeding device is often so small relative to the size of the furnacethat it can be mounted on a support or bracket fastened high on a wallof the furnace so that operators and charging cars may pass thereunder.As a specific example, areel about 5 feet in diameter and about l/2 footwide, holding 32 turns of standard Vg-inch steel pipe (about 530 linearfeet of pipe), is designed for use with a conventional open hearthfurnace. If desired, the feeding device of this invention may be mountedabove the furnace and the pipe fed into the molten bath through anopening in the roof of the furnace.

It will be noted this invention provides an improved apparatus forfeeding a gas beneath the surface of a bath of molten metal, whichapparatus is compact and notwithstanding this, can feed relatively longlengths of pipe, is simple in design and eillcient in operation,occupies little space so that it does not interfere with the chargingequipment or the operators of the furnace, and requires little attentiononce the operation of the feed rolls is commenced until substantiallyall of the pipe has been consumed.

Since different embodiments of the invention can be made withoutdeparting from the scopeof this invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawing shall be interpreted as illustrative and not in a limitingsense. Thus while a cylindrical pipe has been shown in the drawing theinvention comprehends pipe of other shapes. Accordingly, the term pipe"is used in the claims in a broad sense to include pipe of any desiredcross sectional configuration.

What is claimed is:

1. Apparatus for feeding gas into a bath of molten metal beneath thesurface thereof, which comprises a reel, a, metal pipe wound on saidreel, a gas supply pipe communicating with one end of said wound pipe,and motor driven means for pulling said wound pipe from said reel andfor feeding the other end of said pipe into the bath of molten metal tomaintain the said other end of said pipe beneath the surface of the bathof molten metal.

2. Apparatus for feeding gas into a bath of molten metal beneath thesurface thereof, which comprises a rotatable reel, a metal pipe wound onsaid reel to provide a plurality of convolutions of pipe thereon, a gassupply pipe communicating with one end of said pipe, motor-driven feedrollers for pulling said wound pipe from said reel, and means forstraightening said pipe as it is pulled from said wheel, said feedrollers being constructed and arranged to feed the other end ofsaid-`pipe into the bath of molten metal.

3. Apparatus for feeding oxygen into a bath of molten iron in an openhearth furnace, which comprises a rotatable reel, said reel having ahollow shaft, an oxygen supply line connected with said hollow shaft, asteel pipe wound on said reel, said pipe having one end communicablyconnected with said hollow shaft and having the otherend extending fromsaid reel into the said bath of molten iron, motor-driven feed rollersto pull said wound pipe from said reel and to feed the said other end ofsaid pipe into the said bath of molten iron, and means for straighteningsaid pipe as it is pulled from said reel.

4. Apparatus for feeding oxygen into a bath oi molten iron in an openhearth furnace, comprising a support disposed near said open hearthfurnace, a reel removably mounted in said support, said reel having ahollow shaft, a pipe receiving cylindrical portion. a plurality ofconvolutions of steel pipe mounted on said receiving portion, said steelpipe having one end extending through said pipe receiving portion andconnected with said hollow shaft, and the other end extending in asubstantially straight line direction into said open hearth furnacebeneath the surface of the molten bath therein, an oxygen supply linecommunicably connected with said hollow shaft, a pair of straightening:rollersl disposed, one below and the other above said pipe betweenwhich pair of rollers the pipe passes, a pair of feed rollers forfeeding said pipe to effect the unwinding thereof from said reel, thepassage thereof through said straightening rollers and the feeding ofthe straightened pipe into said open hearth furnace, and a variablespeed motor for driving said feed rollers to maintain the free end ofsaid pipe immersed in the molten bath in said open hearth furnace.

5. Apparatus for feeding gas into a bath of molten metal, comprising asupport disposed near said bath, a, reel removably mounted in saidsupport, a metal pipe wound on said reel, one end of said wound pipecommunicating with a sas supply pipe and the other end extending in aNumber p substantially straight line direction into said bath. 1 188,377a plurality of rollers and 9, motor associated 2'267175 therewitharranged to pull said wound pipe from 5 2'343899 said reel and toadvance the said other end of said pipe in a substantially straight linedirection l into said bath. Number EVAN A. JOHNSON. Jn. 492,317

REFERENCES CITED 'I-he following references are of record in the tile oithis patent: f

UNITED STATES PATENTS Name Date Jones June 20, 1916 Skriba Dec. 23, 1941Groll Mar. 14. 1944 FOREIGN PATENTS Country Date Germany Ebb. 26, 1930

